Patrick Clery
Posted on October 12, 2019
Speed up test-driven development with looser or stronger type-checking in your RSpec tests
The rspec-dry-types gem is a drop-in replacement for RSpec's be_a_kind_of()
that allows you to TIGHTEN or LOOSEN what object types you expect returned.
Powered by the dry-types gem, you can find a list of all the reference keys for supported types dry-types documentation for "Built-in Types".
USAGE:
require 'dry-types'
require 'rspec/expectations'
require 'rspec/matchers/be_of_type'
RSpec.describe "check types using be_of_type" do
include RSpec::Matchers::DryTypes
it 'can use a symbol to expect a dry-type' do
expect('a string').to be_of_type(:string)
expect(123).to be_of_type(:integer)
expect(0.123).to be_of_type(:float)
expect("123").to be_of_type(:integer, strict: false)
expect(nil).to be_of_type(:string, strict: false)
expect(nil).to be_of_type(:nil)
end
# Strings must reference the dry-types docs
it 'can use string to expect a dry-type' do
expect('a string').to be_of_type('string')
expect('a string').to be_of_type('strict.string')
expect(123).to be_of_type('integer')
expect(123).to be_of_type('strict.integer')
expect(0.123).to be_of_type('float')
expect(0.123).to be_of_type('coercible.integer')
expect("123").to be_of_type('integer', strict: false)
expect(nil).to be_of_type('string', strict: false)
expect(nil).to be_of_type('nil')
end
# Strings must reference the dry-types docs
it 'is backwards compat with be_a' do
expect('a string').to be_a(String)
expect('a string').to be_a_kind_of('strict.string')
expect(123).to be_an(Integer)
expect(123).to be_an('integer')
end
it 'can use a class to check if its a type' do
# Check inheritance
expect(String).to be_of_type(Object)
expect('a string').to be_of_type(Object)
expect(123).to be_of_type(Object)
# Check coercion
expect(123).to be_of_type(String, strict: false)
expect(0.123).not_to be_of_type(Integer)
expect(0.123).to be_of_type(Integer, strict: false)
end
end
💖 💪 🙅 🚩
Patrick Clery
Posted on October 12, 2019
Join Our Newsletter. No Spam, Only the good stuff.
Sign up to receive the latest update from our blog.